Process and device for generating resonance phenomena in particle suspensions

ABSTRACT

A method and a device for position and/or type-selective control of the position and/or change of position of suspended particles in a multielectrode system by the effect of polarization forces that are induced in the particles by alternating electric fields in the multielectrode system, which particles comprise biological or synthetic objects with dimensions essentially corresponding to those of biological cells or cell organelles, viruses or macromolecules, base on the fact that the multielectrode system forms with the particle suspension an electrical network, in which means of resonance are provided for creating a resonant increase or damping of the field strength of the alternating electric fields at certain frequencies in at least one locally demarcated region of the multielectrode system.

This application claims the benefit under 35 U.S.C. §371 of prior PCTInternational Application No. PCT/EP96/05244 which has an Internationalfiling date of Nov. 27, 1996 which designated the United States ofAmerica, the entire contents of which are hereby incorporated byreferences.

BACKGROUND OF THE INVENTION

The invention concerns a method and a device for position and/ortype-selective control of the position and/or change of position ofsuspended particles in a multielectrode system with the features of thepreambles of patent claims 1 or 9, and especially planar andthree-dimensional microelectrode configurations in semiconductor chipsize, or a method of moving, holding, measuring or sorting suspendedartificial or living particles (e.g. cells) or organic particles ofmicroscopic size in fluids. For individual handling and/orcharacterization of such particles, and especially for directing them ina field gradient or traveling electric field, dielectric polarizationforces are used that are generated by alternating electric fields andamplified by resonance phenomena.

Two basic principles are currently known by which electrical handlingand characterization of individual objects can be performed: 1. thegeneration of field gradients in high-frequency alternating fields(Pohl, H. P., Dielectrophoresis, Cambridge University Press [1978]) and2. application of rotating fields with a tunable rotation frequency(Arnold, W.-M. and Zimmermann, U., Z. Naturforsch. 37c, 908 [1982]).Related fields, but not included here, like electrophoresis and otherdirect-voltage techniques can also be used in part for the namedparticles but are not comparable in their effectiveness.

The first principle mentioned above leads to asymmetric polarization ofmicroparticles, producing, (depending on the nature of the polarization,motion in the direction of higher or lower field strength. This responseis termed positive or negative dielectrophoresis (Pohl, H. P.,Dielectrophoresis, Cambridge University Press [1978]) and has been usedfor more than 30 years to move and separate suspended dielectric bodiesand cells. In recent years dielectrophoretic principles have come intowider use in the biological/medical field through the introduction ofsemiconductor microelectrode systems (Washizu, M. et al., IEEE Trans.IA, 25(4), 352 [1990]; Schnelle, T. et al., Biochim. Biophys. Acta 1157,127 [1993]).

The second of the principles mentioned above, the application ofrotating fields of variable frequency (this category also includeslinear traveling fields (Hagedorn, R. et al., Electrophoresis 13, 49[1992])), is used to characterize the passive electrical features ofindividual suspended particles, and especially of cells (Arnold, W.-M.and Zimmermann, U., Z. Naturforsch. 37c, 908 [1982]; Fuhr, G. et al.,Plant Cell Physiol. 31, 975 [1990]). The principle can be summarized asfollows. A particle is located in a circular electrode configurationwith a rotating field with a speed of a few hertz to several hundredmegahertz. Because of the viscosity of the solution, it reacts like therotor of a dielectric asynchronous motor. In the case of cells withtheir extremely complex structure (cell wall, membrane, organelles,etc), the frequency spectra of the rotation (particle rotation as afunction of the rotation frequency of the field) allow far-reachingconclusions about the physiology and the characteristics of individualcomponents of the same (Arnold, W.-M. and Zimmermann, U., J.Electrostat. 21, 151 [1988]; Gimsa et al. in Schutt, W., Klinkmann, H.,Lamprecht, I., Wilson, T., Physical Characterization of BiologicalCells, Verlag Gesundheit GmbH, Berlin [1991]).

All alternating electric field methods make use of polarization forcesresulting from the relaxation of induced charges. What is ofdisadvantage is the half width of the dielectric dispersions, which areapproximately of the order of a frequency decade (Pohl, H. P.,Dielectrophoresis, Cambridge University Press [1978]; Arnold, W.-M. andZimmermann, U., J. Electrostat. 21, 151 [1988]). This means thatdifferentiation or differentiated movement of different particlesrequires relatively large differences in the structure or the dielectriccharacteristics. A further problem, especially as the particle radiusreduces, is that other forces (local flow, thermal motion, etc) gain ininfluence and even exceed the polarization forces at a particle radiusof less than a micrometer. With colloidal particles, wherepolarizability is far less than that of biological cells, thedisadvantage is that relatively high control voltages (three to tentimes as high) have to be applied to achieve the same force effects.

This is the reason why the two principles mentioned above could only beused to date for relatively large particles, and why a possibility haslong been sought of amplifying the field effects.

SUMMARY OF THE INVENTION

The object of the present invention is to show an improved method forlocal and/or type-selective control of the position and/or change ofposition of suspended particles in a multielectrode system and a devicefor its implementation, with which, without increasing the fieldamplitude, substantial amplification of the polarization forces isachieved at previously determined frequencies and the natural frequencywidth of the force effects, resulting from the dielectric dispersions,is markedly reduced or narrowed down. This object is achieved by amethod and a device with the features of patent claims 1 or 9.Advantageous embodiments of the invention are defined in the subsidiaryclaims. Preferred uses of the invention are stated in claim 20.

In particular electrode systems are to be shown in which amplificationof the polarization forces in locally limited areas (typically a fewhundred micrometers and less in all three dimensions) is produced on thebasis of frequency selective amplification of the electric field forcesby generating spatially limited resonances.

The multielectrode systems according to the invention are, in the firstplace, open oscillating circuit systems in which, at the frequencyinterval considered (≧100 kHz), no resonance phenomena would beexpected. As part of the present invention it was nevertheless found,surprisingly enough, that the open oscillating circuit systems formclosed networks through the particle suspensions, in which resonancescan be achieved especially in low frequency regions.

The use of extremely miniaturized electrode systems (typically in themicrometer range in two dimensions, a few millimeters and less in thethird dimension) and their planar or three-dimensional configuration orinterconnection with capacitive, inductive and resistive elements plusthe application of high-frequency electric fields (e.g. f>10 kHz) of anamplitude in the mV to V range allow the generation of local resonancephenomena within the microstructure that increase the field amplitude atthese points by a multiple. Since the polarization forces areproportional to the square of the field strength, multiplied particlerepelling or attracting forces appear (two to 1000 times and more), thatcan be used to achieve the above stated object.

According to the invention the microelectrodes are arranged, selected intheir geometry or coated or underlaid with materials so that predefinedcapacitive, inductive and resistive components determine the electricalhigh-frequency characteristics of each electrode with the suspensionmedium surrounding it. The components of the individual electrodes,after electrical connection through the particle suspension, formnetworks with resonance phenomena that are arranged precisely on asubstrate (glass, silicon, etc) so that the field strengths areincreased by resonance where particles are to be handled or measured,e.g. in the electrode interspace. The generation of resonances can besupported or shifted and determined in frequency by integrating furthercomponents or connecting external capacitors, inductors and resistors.Calibration of the resonance frequency is possible during operation.This effect can be used both for particle orientation, movement andholding and for dielectric measurement.

The resonance effects can be applied selectively, just for a certainspectral component of the driving signal, by using different signalshapes for the electrode control. Possible are sinusoidal, squarewave,triangular or other periodic and aperiodic signals. Depending on theextent to which the Fourier series have fundamentals and harmonics fordescribing these signals, resonances of the fundamental as well as itsharmonics can be used.

Local restriction of the resonances to one or more areas of less than acubic millimeter is determined by the design of the ends of theelectrodes (circular, series, facing, etc) and the nature of thesuspension solution. From an electronic viewpoint these configurationsare to be seen as systems not terminated with a defined impedance. Aswill be shown in the examples however, electrode configurations can befound in which the terminating impedance of the solution merelydetermines the amplitude of the resonances, not their frequency.

In contrast to the resonance effects known in electronics, the polarizedparticles and cells of the invented method are to be regarded as samplebodies for the resonance-related increase of field strength inside thedielectric (fluid) of a capacitor, whose presence in turn influences theresonance phenomena of the system and can be utilized by tuning theresonant frequency for particle separation, collection and holding.

Especially effective is the integration of tunable capacitive, inductiveand/or resistive elements with which individual electrodes can bematched individually or resonances defined in frequency and altered byprograms. The advantage of this is that, while keeping the sameelectrode configuration, polarization forces can be amplified or dampedfrom the exterior as a function of frequency. This effect can be used toseparate individual particle classes with the same or similar dielectriccharacteristics from other particle types.

The following principles can be applied for calibrating and controllingthe required resonant effect:

1. Active tuning of the oscillating circuit elements, e.g. capacitors,inductors and resistors.

2. Application of two or more fields of the same or opposing sense ofrotation of different frequency.

3. Application of fields as in point 2 with different but adjustableamplitude.

4. Application of fields as in point 2 with different exposure time ofthe fields.

5. Application of fields as in point 2 with calibration between theirfrequencies.

6. Application of periodic signals with different harmonic content.

7. Combination of the principles stated in points 1 through 6.

In practice the generation of resonances in microelectrode systemsaccording to the invention can be produced as follows:

It is possible to set the conditions for resonance bydimensioning/shaping the electrodes while allowing for the concreterequirements of microstructuring. Thus the electrode system shown inFIG. 1 for example, ie the corresponding equivalent circuit diagram inFIG. 2, can be analyzed and modeled by common methods of computer-aidenetwork analysis (computation of voltages at random points in thenetwork).

The necessary characteristics of the electrode system can also bedetermined by experiment. For this purpose a network (equivalent circuitdiagram) corresponding to an electrode system is realized and measured,while any extra external capacitors and/or inductors are added andtuned. This procedure is preferred especially if the number ofelectrodes is relatively high (e.g. ≦8).

In the implementation of values determined by experiment, there areagain two practicable procedures. Firstly, it is possible whenprocessing the electrodes, using semiconductor technology for example,to integrate the calculated switching elements on the chip. Theadvantage of this is that the capacitive/inductive elements themselvestake on dimensions in the micrometer region and have virtually noreaction on the circuit of the generator. Secondly, the chip can bewired with external components. The disadvantages of this are thereduced design possibilities and the but indirect effect of thecomponents in the electrode space because of their input leads.

Finally it is possible to integrate controllable components on the chipin the multielectrode system. These include in particular activecomponents like switching diodes, transistors and controllablevariable-capacitance diodes etc. The advantage here is that theresonances can be tuned one after the other, allowing external computercontrol of the system. A further variant in this context is the use ofmechanical means of setting that make use of magnetic or piezoelectriceffects (e.g. field influence in FET).

The processing of planar electrode structures using semiconductortechnology offers a variety of possibilities, because capacitive,inductive and resistive elements in the micrometer region can beimplemented. The advantage of this configuration, compared to externalwiring, is that the networks can be arranged so that the electrodes arenot wired uniformly but in a definable manner. This principle alsoassists considerably in spatial limiting of the resonance phenomenon onthe chip or the microstructured surface.

The multielectrode configuration according to the invention can comprisetwo, three, four or more electrodes for example. It can be enclosed inchip form in a ceramic package with electric leads.

Preferred examples of design of the invention are explained in moredetail below with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a section from a microstructured surface;

FIG. 2 illustrates a simplified equivalent circuit diagram for theelectrode configuration shown in FIG. 1;

FIG. 3 shows the rotation speed spectrum of sephadex particles of 70 μmdiameter;

FIGS. 4A and 4B show the influence of a resonance on the rotation of twodielectric particles of slightly different characteristics;

FIG. 5 presents a resonant structure in which the region 51 is kept freeof cells and particles by an electric field;

FIG. 6 shows a traveling-wave dielectrophoretic structure;

FIG. 7 shows a planar matrix resonant structure for particle and cellhandling; and

FIG. 8 shows a resonant structure for separating suspended particles orcells in a solution channel 83 by diffusion and field forces.

Four electrodes 10a-d, 12a-d, 13a-d (black) are shown, enclosing acentral area 14 with a suspended particle of about 100 μm diameter orless. The electrodes are designed so that capacitive and inductivecomponents appear when they are driven by alternating voltage. Byunderlaying a widened metal layer 12a-d (e.g. gold, 1 μm thick, 100 μmwide) with a dielectric 11a-d (dielectric constant as high as possible),a capacitor is formed that is taken to ground (here the schematicallyillustrated substrate 16). The meander-shaped leads 13a-d increase theinductances of the electrode leads. As a result of the way in which theelectrodes are faced and the electrical connection of the electrode endsin the central area 14 through the suspension solution, the inductive,capacitive and resistive electrode components are linked into anelectronic network. Depending on whether the electrodes are of identicalor differing design, resonances can be generated in the central area 14of the electrodes that increase the field forces on the particle by amultiple compared to the same driving amplitude of the electrodeswithout the described configuration (in electrolyte solutions that canmean values between >1 and 1000 or more for example). The conductivityof the suspension solution damps the height of the resonance however.

FIG. 2 is a simplified equivalent circuit diagram for the electrodeconfiguration shown in FIG. 1. It can be seen that the interconnectionof the lead capacitances 21a-d, of the electrode inductances 22a-d, ofthe suspension solution resistances 23a-d between the electrodes and thecapacitances between the electrodes 24a-d produces a network with fourinput poles 25a-d. This system, driven by alternating voltage (pole25a-phase=0°, pole 25b-phase=180°, pole 25c phase=0°, pole25d-phase=180°) but also when excited by a rotating field (pole25a-phase=0°, pole 25b-phase=90°, pole 25c-phase=180°, pole25d-phase=270°), shows a marked resonant response. The frequency can bedefined very precisely by the inductances and capacitances.

FIG. 3 shows the rotation speed spectrum of sephadex particles of 70 μmdiameter. A microchamber according to FIG. 1 was used for measurement,driven by four squarewave signals of 2 V_(Pp) offset in phase by 90°.The interval between two opposing electrodes was 100 μm, and a waterysolution was used. When driven by a voltage constant over the entirefrequency range, a Lorentz spectrum was obtained (). After integrationof inductive and capacitive elements on the microchamber chip oneobtains the spectrum altered by resonance phenomena within the centralarea of the microchamber (□). What is especially noticeable here is theincrease in angular momentum at the resonant frequency f_(res) by afactor of more than 30, and its reduction at a third of f_(res). Thisreduction is due to the resonance amplification of the third harmonic atthe test frequency 1/3 f_(res). The cause of this is the opposing senseof the third harmonic compared to the fundamental.

The quadrupole electrode system illustrated in FIGS. 1, 2 and 3 issuitable for centering or holding a particle or aggregation ofparticles, especially at the resonant frequency, and also for measuringindividual particles (e.g. cells) in the rotating field. The rotationalspeed of the particle increases very sharply and evidently at resonanceas a function of the rotation frequency of the field. If squarewavefields are applied, harmonics of the fundamental appear and thus furtherresonance in the frequency layers of the forces acting upon theparticles.

FIGS. 4A and 4B show the influence of a resonance on the rotation of twodielectric particles (here living cells of vegetable or animal origin)of slightly different characteristics (dielectric constant and/orconductivity) and thus the differentiation of microscopic particles inthe high-frequency rotating field. Curve 41 is the rotation(rot=rotational speed as a function of the rotational frequency of thefield (f)) without resonance for the particle of type 1 (e.g. a cell 1).There is rotation of the cell both opposite to the sense of the field(low frequencies) and in the sense of the rotating field (highfrequencies). Curve 42 shows the corresponding effect for a particle oftype 2 (e.g. a cell 2). If the resonance is in the vicinity of the zerocrossing of the two rotation spectra, the transition in rotation (changeof direction) becomes extremely sharp (curve 42→curve 43, curve 41→curve44). Under these conditions the differences in the dielectriccharacteristics of the two particles are made use of to move them fastin different senses of rotation. The advantage of this in conjunctionwith resonance is that particles which only differ slightly in theirrotation spectrum in this frequency range nevertheless rotate oppositeto one another as in curves 43 and 44. Consequently the particles arevery easily identified and separated. Particles in traveling electricfields would exhibit the same response, and here the opposed movement ofthe particles at resonant frequency can be used directly for separation.

FIG. 4B shows the same resonance effect of the dielectrophoretic forcesthat drive a particle in the field gradient (45--force spectrum of cellsof type 1, 46--force spectrum of cells of type 2, 47--alteration ofspectrum upon appearance of resonance of cell of type 1, 48--alterationof spectrum upon appearance of resonance of cell of type 2).

FIG. 5 presents a resonant structure in which the region 51 is kept freeof cells and particles by an electric field. The resonant arrangement ofinductances 53A and 53B and capacitances 55A and 55B is used to amplifythe field in the region 51. The constantly present capacitance of thecomb structure 51 is increased by underlaying the electrodes with thedielectric 52A and 52B. The region 51 can be of sieve-like design sothat the solution passes through the structure while the particles areheld back by the electric field. The element 56 can be used as a tuningelement to adjust the resonant frequency. It is processed on thesubstrate or shifted micromechanically or by other means over theregions 52 causing capacitive changes that tune the oscillatingcircuits.

FIG. 6 shows a traveling-wave dielectrophoretic structure. Particlemotion is induced between and/or over the comb-like arrangement ofmicroelectrodes 61. If the structure is driven by mixed sinusoidalsignals (e.g. squarewave signals with a duty factor of 1:1) according tothe gives phase, the inductances 63 and capacitances 62 can be designedso that the required harmonic of the control signal is amplified byresonance. In this way it is possible, for example, to give thisharmonic the same amplitude in the comb structure as the fundamental.Depending on the phase relation of the harmonic frequencies, two opposedtraveling fields of a certain frequency relation (e.g. f and 3*f) can heinduced for instance.

FIG. 7 is a planar matrix resonant structure for particle and cellhandling. A large quantity of particles or cells of a suspension can behandled simultaneously in this structure. The suspension in the regions74 has electrical contact to the electrodes 71, direct or by way of acapacitively acting insulating layer. To drive the structure, foursignals offset in phase by 90° are applied to the points 73A, 73B, 73Cand 73D. Connection with suitable inductances 72 produces an increase infield strength resonance and corresponding amplification of the fieldforces on individual particles or cells in the solution regions 74. Thenumber of particles in each solution region 74 influences resonancewithin this solution region and leads to a decrease in the field forcesacting upon further particles for example. This response in the proposedstructure makes it possible to fill all solution regions equally.

FIG. 8 shows a resonant structure for separating suspended particles orcells in a solution channel 83 by diffusion and field forces. Thestructure is driven pulsed or continuously through the leads 81 and 84so that the particles or cells travel along the channel 83 in motioninduced alternately by diffusion and field force. Particles with a highdiffusion coefficient and low positive dielectrophoresis will travelespecially fast. If the structure is operated so that the suspensionmeans sets the capacitance of the electrodes 82 referred to the commoncounter-electrode so that there is an increase in the resonance of thefield, the presence of particles would alter this capacitance and reducethe field strength here. In this way diffusion predominates over thecollecting field forces and undesired accumulations of the particles orcells that are to be separated are thus avoided.

There are uses for the invented device in the sorting and separating ofparticle mixtures, in medical, biological, biotechnical, physical andchemical applications, especially in conjunction with the verification,characterization and identification of cells, organelles, viruses andmacromolecules, in the powering of dielectric micromotors ormicroactuators of a rotation or linear type, in the directing, sorting,measuring, positioning, destruction and modification of suspendedparticles, in microhandling devices, in the assembly and encapsulationof pharmaceutical products, in the shaping of microparticles, inmicrochemistry (especially for synthesizing fluid or solid phases, whichcan be held, combined, made to react, divided and/or separated by theresonance principle of the invention), or in combination withspectroscopic methods of measurement (especially with the fluorescencecorrelation spectroscopy described in publication WO 96/16313 or other,in particular confocal fluorescence measurement methods as described inpublication WO 96/13744 for example and European patent application no.96 116 373.0.

We claim:
 1. Method for position and/or type-selective control of theposition and/or change of position of suspended particles in amultielectrode system by the effect of polarization forces that areinduced in the particles by alternating electric fields in themultielectrode system, which particles comprise biological or syntheticobjects with dimensions essentially corresponding to those of biologicalcells or cell organelles, viruses or macromolecules, characterized inthat the polarization forces are amplified or reduced by increasedresonance or damping of the field strength of the alternating electricfields at certain frequencies in at least one locally demarcated regionof the multielectrode system, the alternating electric fields includingalternating, rotating or traveling electric fields so that, in circularand/or linear multielectrode configurations, there is rotation,translation or positioning of particles induced by the principle ofelectrorotation, dielectrophoresis, levitation or traveling-wavetechnology, whereby certain frequency ranges of the particular motionare amplified or damped by the resonance phenomena.
 2. Method accordingto claim 1 in which the resonant change of field strength is achieved bythe external adjustment of controllable components provided in themultielectrode system.
 3. Method according to claim 1 in which theresonant increase of field strength is influenced selectively by thepassive electrical characteristics of the particle suspension, whereby,especially through the presence or passage of one or more particles in aregion in the multielectrode system, the electrical characteristics ofthe suspension at this point are altered so that the resonant responseof the microstructure is altered, defined or electronically tuned sothat the resonance conditions, possibly selective in time throughalteration of the passive electrical characteristics of the suspension,are only achieved or terminated until the presence or passage of acertain particle type by this particle itself.
 4. Method according toclaim 1 in which the resonant increase of field strength is achieved ata certain fundamental of the alternating electric fields and/ormultiples of the fundamental with amplification by a factor of approx.two to 1000, whereby in particular the alternating electric fields aregenerated by periodic control voltages of a frequency ≧100 Hz withamplitudes between 0.1 and 200 V and the periodic signals applied forfield generation can be sinusoidal, triangular, squarewave, tristate orcombinations of these signals, of which certain Fourier components arepossibly amplified by the resonance, which Fourier components of theperiodic control signal can simultaneously generate field components ofdifferent rotation or translation sense, whereby the amplitudes of theFourier components of the field can be attuned to one another by theresonance.
 5. Method according to claim 1 in which holding of theparticles is amplified or damped by the resonance phenomena.
 6. Methodaccording to claim 1 in which the particles comprise a mixture ofdifferent types of particles and the resonances alter the motion of partor all of these particle types, whereby one or more particle types alterfrom negative to positive dielectrophoresis at the resonant frequency orthe sense of particle rotation or motion in the traveling-wave field. 7.Method according to claim 1 in which two or more field frequencies aremodulated or used simultaneously by different electrode subsystems orused alternating with the same or opposite sense of rotation ortranslation and adjustable amplitude in that the resonant frequency isapplied to ranges of the dielectric particle spectrum (force as functionof frequency) where the particle types differ.
 8. Device for positionand/or type-selective control of the position and/or change of positionof suspended particles in a multielectrode system by the effect ofpolarization forces that are induced in the particles by alternatingelectric fields in the multielectrode system, which particles comprisebiological or synthetic objects with dimensions essentiallycorresponding to those of biological cells or cell organelles, virusesor macromolecules, characterized in that the multielectrode system formswith the particle suspension an electrical network, in which resonancemeans are provided for creating a resonant increase or damping of thefield strength of the alternating electric fields at certain frequenciesin at least one locally demarcated region of the multielectrode system,resonance means being formed by the capacitive and/or inductive designof the electrodes of the microelectrode system.
 9. Control deviceaccording to claim 8 in which means the resonance are formed bycontrollable components integrated into or added to the multielectrodesystem.
 10. Control device according to claim 8 in which the resonancemeans are formed by the particle suspension, especially the particlesthemselves as components of the electrical network.
 11. Control deviceaccording to claim 8 in which the microelectrode configurations exhibittypical gap dimensions from 10 nm to several hundred μm and in whichrotating or alternating electric fields are generated.
 12. Controldevice according to claim 8 in which the microelectrode configurationshave three-dimensional structures or multilayer structures on asubstrate consisting of glass, semiconductor material, plastic orceramic.
 13. Control device according to claim 8 in which the substratehas structures, passive components, areas with channels, walls,trenches, cutouts or barriers, and/or micromechanical elements likevalves, membranes, shiftable elements or moving arms for tuning theoscillating circuits, or in which the output stages or the entirehigh-frequency generator for producing the electrode signals and/ordriving the components to control the resonant frequencies areintegrated on the substrate.
 14. Control device according to claim 8 inwhich several microelectrode systems are configured next to one another,back to back, offset, facing one another, as a cascade, in a ring orstacked.
 15. Control device according to claim 8 in which components areprovided with which the resonant frequencies are controlled and whichcan be operated by a control program, which components are formed ofactive components like variable-capacitance diodes, field-effecttransistors and adjustable inductors, whereby the alterations in theresonance phenomena can also be generated by connecting, disconnectingor bypassing components of the oscillating circuits.
 16. Control deviceaccording to claim 8, in which the electrodes on essentially planar,insulating mounts form at least an open electrode system that hascapacitive, inductive and resistive components and is connected throughthe particle suspension solution to at least one network-typeoscillating circuit system.
 17. Control device according to claim 16, inwhich the electrode system takes the form of meanders and/or loopscovered by the insulating layers, which form networks with alteredinfluence of capacitive and/or inductive elements, whereby separateresonance regions influence one another.
 18. Method for position and/ortype-selective control of the position and/or change of position ofsuspended particles in a multielectrode system by the effect ofpolarization forces that are induced in the particles by alternatingelectric fields in the multielectrode system, which particles comprisebiological or synthetic objects with dimensions essentiallycorresponding to those of biological cells or cell organelles, virusesor macromolecules, characterized in that the polarization forces areamplified or reduced by increased resonance or damping of the fieldstrength of the alternating electric fields at certain frequencies in atleast one locally demarcated region of the multielectrode system, two ormore field frequencies being modulated or used alternating with the sameor opposite sense of rotation or translation and adjustable amplitude inthat a resonant frequency is applied to ranges of the dielectricparticle spectrum of said particles where the particle types differ. 19.Device for position and/or type-selective control of the position and/orchange of position of suspended particles in a multielectrode system bythe effect of polarization forces that are induced in the particles byalternating electric fields in the multielectrode system, whichparticles comprise biological or synthetic objects with dimensionsessentially corresponding to those of biological cells or cellorganelles, viruses or macromolecules, characterized in that themultielectrode system forms with the particle suspension an electricalnetwork, in which resonance means are provided for creating a resonantincrease or damping of the field strength of the alternating electricfields at certain frequencies in at least one locally demarcated regionof the multielectrode system, the electrodes on essentially planar,insulating mounts forming at least an open electrode system that hascapacitive, inductive and resistive components connected through theparticle suspension solution to at least one network-type oscillatingcircuit system, the electrode system being in the form of meandersand/or loops covered by the insulating layers, which form a network withaltered influence of capacitive and/or inductive elements, wherebyseparate resonance regions influence one another.